Rule 23

(ii) a second
masthead light abaft and higher than the forward one; except that
a vessel of less than 50m in length shall not be obliged to exhibit
such light but may do so;

(iii) sidelights;

(iv) a sternlight.

(b) An air-cushion
vessel operating in the non-displacement mode shall, in addition to
the lights prescribed in paragraph (a) of this Rule, exhibit an all-round
flashing yellow light.

(c) A WIG craft
only when taking off, landing and in flight near the surface shall,
in addition to the lights prescribed in paragraph (a) of this Rule,
exhibit a high-intensity all-round flashing red light.

(d)

(i) A power-driven
vessel of less that 12 metres in length may in lieu of the lights
prescribed in paragraph (a) of this Rule exhibit an all-round white
light and sidelights;

(ii) a power-driven
vessel of less than 7 metres in length whose maximum speed does not
exceed 7 knots may in lieu of the lights prescribed in paragraph (a)
of this Rule exhibit an all-round white light and shall, if practicable,
also exhibit sidelights;

(iii) the masthead
light or all-round white light on a power-driven vessel of less than
12 metres in length may be displaced from the fore and aft centreline
of the vessel if centreline fitting is not practicable, provided that
the sidelights are combined in one lantern which shall be carried on
the fore and aft centreline of the vessel or located as nearly as practicable
in the same fore and aft line as the masthead light or the all-round
white light.